[Healeys] Sidescreen fixing wing nuts

[Per Schoerner]

Hi
Helping a friend with his BN4, it's one of those fairly early ones built 
in Longbridge. As far as I understand it should have the one eared wing 
nut to fix the sidescreen to the door. It seems that the size of the 
stud on the rear fixing plate is 3/8 UNF, whereas it is 5/16 UNF on my 
3000. Is this correct? Also, should the front nut also be of the one 
eared type.

Best regards, Per in Sweden